[WebAssembly] Fix updating/moving DBG_VALUEs in RegStackify

Summary:
As described in PR40209, there can be issues in DBG_VALUEs handling when multiple defs present in a BB. This patch
adds logic for detection of related to def DBG_VALUEs and localizes register update and movement to found DBG_VALUEs.

Reviewers: aheejin

Subscribers: mgorny, dschuff, sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D56401

llvm-svn: 351216

1 files changed, 38 insertions, 0 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyDebugValueManager.h b/llvm/lib/Target/WebAssembly/WebAssemblyDebugValueManager.h
new file mode 100644
index 0000000..73f3172
--- /dev/null
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyDebugValueManager.h
@@ -0,0 +1,38 @@
+// WebAssemblyDebugValueManager.h - WebAssembly DebugValue Manager -*- C++ -*-//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the declaration of the WebAssembly-specific
+/// manager for DebugValues associated with the specific MachineInstr.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYDEBUGVALUEMANAGER_H
+#define LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYDEBUGVALUEMANAGER_H
+
+#include "llvm/ADT/SmallVector.h"
+
+namespace llvm {
+
+class MachineInstr;
+
+class WebAssemblyDebugValueManager {
+  SmallVector<MachineInstr *, 2> DbgValues;
+
+public:
+  WebAssemblyDebugValueManager(MachineInstr *Instr);
+
+  void move(MachineInstr *Insert);
+  void updateReg(unsigned Reg);
+  void clone(MachineInstr *Insert, unsigned NewReg);
+};
+
+} // end namespace llvm
+
+#endif